Inertia vacuum assisted self-priming pump

ABSTRACT

An inertia vacuum assisted self-priming pump, characterized by comprising a centrifugal pump and a rotary vacuum pump, wherein a pedestal is fixed above a frame of the centrifugal pump, a rotary vacuum pump is mounted above the pedestal and covered by an enclosure; The centrifugal pump consists of an eccentric reducer, a suction cover, a volute, an impeller, a casing cover, a shaft, an adaptor, a frame and a discharge check valve.

TECHNICAL FIELD

The present invention relates to the field of centrifugal pumps, and particularly to an inertia vacuum assisted self-priming pump.

BACKGROUND

A centrifugal pump is the most common pump conveying liquid from one place to the other place, which is used for irrigation, domestic water systems, sewage treatment and various other applications. Liquid is driven by an impeller located in the volute and then is discharged from the suction sump by the volute through the discharge pipe. A volute suction opening is concentric with the impeller. The rotation of the impeller makes the liquid be outwards thrown to the outer edge of the impeller and centrally discharged from the outlet of the volute. When the liquid is outwards driven, vacuum is produced at the center, so that more liquid is sucked in the pump.

One of the main limitations of the use of the centrifugal pump is that: when the pump is filled with air, the impeller can only drive air to rotate, because the weight of air per unit volume is very light, the generated centrifugal force is very small and often cannot discharge the air in the pump volute and the suction pipe, they have no the capability to self-prime liquid to operate. In the field of general purpose centrifugal pumps, in general, dry mounted centrifugal pumps, except self-priming pumps who having self-priming capabilities, most of them prime water depending on positive pressure. there is a need to install a bottom valve at the end of the suction pipe of centrifugal pumps, and the pump can be started only when water is filled in the pump before start for the first time. For example, in dewatering application, the operation of the pump is discontinuous, so there is a need to repeatedly and continuously fill and refill water into the pump manually. Although being provided with a bottom valve, the pump has the main natural defects that: 1. the bottom valve is cumbersome and is difficult to lift, monitor maintain or repair because of being mounted under liquid; 2. because of being immersed under liquid for a long time, the bottom valve may be easily corroded and then the sealing effect may be affected, and may not operate for a secondary start up; 3. solid particles produced in production and processes may enter into the circulating liquid, the accumulation and adhesion of the solid particles in the bottom valve may prevent the bottom valve from being completely sealed, so that the bottom valve may fail immediately; and 4. because the bottom valve is mounted at the end of the suction pipe, the bottom valve may affect the suction area of the pump and then cause a insufficient water supply. In addition, when there is a need to perform field operation or unattended operation, the water source that needs to be drained may be completely drained at any time, however, because it is unattended operation or it cannot be found in time, the water pump is in a dry running state for a long time, it is easy to burn the mechanical seal and even causes the whole machine to be damaged.

In view of the above situation, there is a need to design a vacuum assisted self-priming pump to achieve the following objects:

1. there is no need to mount a bottom valve;

2. the centrifugal pump may automatically evacuate quickly;

3. there is no need to fill water in the pump before first start, and the pump may be waterlessly started directly;

4. self-priming and repeated and lasting self-priming may be achieved;

5. during self-priming, even the pump runs dry for a long time, the pump may not be damaged;

6. after evacuation, when the centrifugal pump starts to operate, the vacuum pump stops operating, and enters a dormant state to greatly save energy, reduce mechanical noise and increase the service life of the vacuum pump.

SUMMARY

The present invention aims to provide an inertia vacuum assisted self-priming pump to solve the problem that the centrifugal pump cannot perform self-priming, cannot perform dry running for long time, and the self-priming device cannot stop after the vacuum pump completes evacuation under the existing technical condition.

To achieve the above purpose, the present invention adopts the following technical solution:

An inertia vacuum assisted self-priming pump, characterized by comprising a dry mounted centrifugal pump, wherein a pedestal is arranged above a frame of the dry mounted centrifugal pump, a rotary sliding vane type of vacuum pump is fixedly mounted above the pedestal, the dry mounted centrifugal pump includes a volute, a suction cover is equipped at the front end of the volute, an eccentric reducer is mounted in front of the suction cover, a discharge flange is arranged at one side of the volute perpendicular to the axial direction, the front end of the discharge flange is connected to a check valve, a rear casing cover is equipped at the rear end of the volute, an oil groove circumferentially surrounding the shaft is arranged outside the seal cavity of the casing cover, the casing cover is backwards connected to an adapter and the frame in sequence, a bearing and the shaft are mounted in the frame, the shaft passes through the frame and then extends out at the driving end to connect an coupling which will be coupled to an engine, and centrifugal pump shaft drive end is connected to a pump shaft of the vacuum pump by a belt, a pulley and an electromagnetic clutch, thus simultaneously rotating or disconnecting together with the shaft of the centrifugal pump, the non-driving end of the shaft passes through the casing cover and then enters into the volute, an impeller is located at the center or a little bit off center of a water passage of the volute and is mounted on the shaft non-drive end, a run dry device is built inside of a vacuum pump's enclosure, the device including an oil reservoir, two hose and one temperature meter, the inner upper part of the oil reservoir is connected with the upper part of the oil groove in the casing cover by an upper oil pipe, the inner lower part of the oil reservoir is connected with the lower part of the oil groove in the casing cover by a lower oil pipe, a circulating oil loop is formed between the oil reservoir and the oil groove, and waterless dry-running protection is achieved using thermosyphon effect of oil.

The vacuum assisted self-priming control device comprises a flow switch, a single or a dual exhaust pipe assembly, an electromagnetic valve, an electromagnetic clutch, a vacuum pump and a controller, wherein the flow switch is normally closed and mounted at the top of the eccentric reducer, the electromagnetic valve is normally closed and mounted on the exhaust pipe assembly, the electromagnetic clutch is normally open and mounted on the shaft drive end of the vacuum pump, the shaft of the vacuum pump is connected to the shaft of the centrifugal pump by a pulley belt assembly and the electromagnetic clutch, the flow switch controls the power source of the electromagnetic valve and the electromagnetic clutch by monitoring the water flow in the eccentric reducer to achieve automatic start/stop, the flow switch and the exhaust pipe assembly provided with the electromagnetic valve are mounted at the top of the eccentric reducer mounted at the front of the suction cover, after the centrifugal pump is started, the normally closed flow switch connected to the controller is turned on, the electromagnetic clutch is turned on and then closed, the vacuum pump starts to run, the electromagnetic valve is turned on and then opened, the vacuum pump starts to evacuate the air from suction pipe and centrifugal pump through the exhaust pipe assembly, after several seconds, when water enters the eccentric reducer, the water flow flushes the flow switch's contactor, the flow switch is turned off immediately, the electromagnetic valve is immediately turned off and closed, meanwhile, the electromagnetic clutch connected to the flow switch and mounted on the pump shaft of the vacuum pump is immediately turned off, the turned-off clutch is detached from the centrifugal pump's shaft, the vacuum pump stops operating and turns into a dormant state, and the vacuum pump completes evacuation.

The vacuum assisted self-priming control device may also comprise a flow switch, a float chamber assembly, an electromagnetic clutch, a vacuum pump and a controller, wherein the float chamber is located at the top of the eccentric reducer, a float chamber cover is mounted at the top of the float chamber, a through hole is set in the central of the float chamber cover, a gasket of float valve, a float ball and a stop motion mechanism are arranged in the float chamber, the stop motion mechanism includes a lever support connected to the bottom of the suction cover, a first lever and a second lever located above the first lever are rotationally mounted on the lever support, one end of the second lever and one end of the first lever are located below the gasket of float valve in sequence, the lower end of the gasket of float valve is connected to the end of the second lever extending below the gasket of float valve, the end of the first lever located below the gasket of float valve is connected to the float ball by a float valve lever and a U clamp, the other ends of the first lever and the second lever are connected by a lever connecting ring, a strainer is arranged above the position where the float chamber is connected with the suction pipe in the float chamber, the flow switch is mounted at the top of the eccentric reducer, the electromagnetic clutch is mounted on the shaft of the vacuum pump, the shaft of the vacuum pump is connected to the shaft of the centrifugal pump by a pulley belt assembly and the electromagnetic clutch, wherein the gasket of float valve floats along with the float ball and vertically moves upwards and downwards in the float chamber to control the opening or closing of the exhaust pipe, after the centrifugal pump is started, the normally closed flow switch connected to the controller is turned on, the electromagnetic clutch is turned on and closed, the vacuum pump starts to evacuate air from the suction pipe and the centrifugal pump through the exhaust pipe assembly, the water will come up through the suction pipe and enter into the float chamber and pump volute, the float ball floats along with the water level until the gasket of float valve is closely attached to the seal seat of float valve to close the exhaust pipe to prevent the water from entering into then vacuum pump, meanwhile, the water flow in the eccentric reducer continues flushing the flow switch's contactor, the flow switch is set to be turned off after a few seconds when the water starts to flushes the flow switch's contactor, when the flow switch turned off, the electromagnetic clutch is immediately turned off, the turned-off clutch is detached from the vacuum pump shaft, the vacuum pump stops operating and enters a dormant state, and the vacuum pump completes evacuation.

The used vacuum pump is a rotary sliding vane type of vacuum pump, comprising a shaft, a volute, a casing cover, a rotor, a push lever and slide vanes, wherein a shaft of the rotary sliding vane vacuum pump is connected to the shaft of the centrifugal pump by the electromagnetic clutch and the pulley belt assembly and is driven to rotate, the slide vanes are driven to rotate close to the inner surface of the chamber of the volute by the rotor, an airtight chamber is formed by two adjacent slide vanes and the inner surface of the chamber of the volute, when the slide vanes rotate from the discharge to the suction: the volume of the airtight chamber is gradually increased and the intensity of pressure is reduced, air is pressed in the airtight chamber when the airtight chamber passes through the suction, the airtight chamber is filled with air and is rotated to the discharge of the pump, the combined total length of the two slide vanes mounted symmetrically about the center and the push lever between the slide vanes is unchanged, the airtight chamber space fitted with the irregular curved surface of the volute is gradually reduced, the intensity of pressure is gradually increased, and air is discharged out of the pump chamber of the vacuum pump when passing through the discharge; this process is repeated so that air at the suction may be quickly moved to the discharge of the volute through the pump chamber and then discharged out of the pump chamber to complete evacuation.

The centrifugal pump discharge flange is installed with a check valve, when the pump discharges, the gasket in the check valve is upwards horizontally stretched to guarantee that liquid pass through freely; when the pump is just started, during evacuation, because of the action of gravity, the gasket is sagged-attached to the check valve, when the pressure in the pump chamber is gradually reduced, the outside atmospheric pressure acts on the gasket, the pressed gasket seals the pump chamber to prevent the outside air from entering.

A built-in oil reservoir is set inside of the vacuum pump's enclosure which is installed on the top of the pedestal to cover the rotary vacuum pump, two hoses was set to connect the oil reservoir and the oil groove; a circulating oil loop is formed between the oil reservoir and the oil groove to protect the mechanical seal in case of pump runs dry. A temperature meter is mounted outside of the oil reservoir to monitor the oil temperature.

The vacuum pump is assembled on a pedestal which is mounted on the centrifugal pump frame, the drive end of vacuum pump shaft is connected by pulley belt assembly and the electromagnetic clutch, the suction of the vacuum pump is connected to the eccentric reducer or to the float chamber by the exhaust pipe assembly, the electromagnetic clutch is turned on and closed after the centrifugal pump is started and then the vacuum pump is started, air inside of the pump and the suction pipe is continuously evacuated into the atmosphere by the vacuum pump through the eccentric reducer or a sealed float chamber, air inside of pump volute and the suction pipe is evacuated so that the pressure inside of the pump volute is reduced and finally vacuum is formed, water in the suction sump gradually enters the suction pipe and pump volute under the action of atmospheric pressure until the pump impeller is fully merged, the water flow flushes the flow switch's contactor so that the flow switch is turned off, the electromagnetic valve is turned off and closed, the electromagnetic clutch is turned off and detached from the vacuum pump shaft, the vacuum pump stops operating, and the centrifugal pump keeps running. Compared with the prior art, the present invention has the advantages that:

1. the pump can evacuate air and self priming quickly;

2. the pump can be waterlessly started and perform waterless dry running;

3. after performing the vacuumization process, the vacuum pump stops operating, and enters a sleep state to greatly reduce energy consumption, reduce mechanical noise and increase the service life of the vacuum pump;

4. the vacuum pump is parasitically mounted on the centrifugal pump without additional power; and

5. the pump is compact in structure, small in volume and light in weight to facilitate maneuver.

DESCRIPTION OF DRAWINGS

FIG. 1 is a structural side view of the first control mode of the present invention.

FIG. 2 is a structural front view of the first control mode of the present invention.

FIG. 3 is a structural side view of the second control mode of the present invention.

FIG. 4 is a structural front view of the self-priming rotor vacuum pump of the present invention.

FIG. 5 is a structural side view of the self-priming rotor vacuum pump of the present invention.

FIG. 6 is a structural schematic diagram of the float chamber of the present invention.

DETAILED DESCRIPTION

The present invention will be described in detail below in combination with the drawings and the embodiments.

Specific Embodiment 1

As shown in FIG. 1-FIG. 5, an inertia vacuum assisted self-priming pump, comprising a centrifugal pump, a vacuum pump 7, and a run dry device 12. The centrifugal pump comprises a volute 17, wherein one side of the volute 17 in the axial direction, i.e. the front side of the volute 17, is connected with an eccentric reducer by a suction cover 19, the other side of the volute 17 in the axial direction, i.e. the rear side of the volute 17, is connected to a casing cover 14 the side of the volute vertically to the axial direction is a clean-out cover 25, the casing cover 14 is axially connected to an adapter 11 and a frame 9 in sequence, a shaft 2 is axially mounted in the frame 9 rotationally by a bearing, the front end of the shaft 2 passes through the casing cover 14 and extends into the volute 17, an oil groove circumferentially surrounding the shaft 2 is axially arranged in the stuffing box of the casing cover 14, and an impeller 16 is axially mounted at the front end of the shaft 2.

An eccentric reducer 21 is mounted at the suction of the centrifugal pump, the top of the eccentric reducer 21 is provided with a flow switch 29 and is equipped with a single or dual exhaust pipe assembly 15 containing an electromagnetic valve 28, and the exhaust pipe assembly 15 is connected to the suction of the vacuum pump 7. The cable led from the controller and go through the flow switch 29 to connected both the electromagnetic valve 28 and the electromagnetic clutch 27. The centrifugal pump volute is interlinked to the vacuum pump 7 when the electromagnetic valve 28 is turned on, and then is dis-interlinked each other when the electromagnetic valve 28 is turned-off and closed. electromagnetic valve 28 and low switch 29 are covered in the protective cover 61.

The run dry device 12 comprises an oil reservoir built inside of the vacuum pump's enclosure 6, wherein oil is filled in the oil reservoir 12, the inner upper part of the oil reservoir is connected with the upper part of the oil groove in the casing cover 14 by an upper oil pipe, the inner lower part of the oil reservoir is connected with the lower part of the oil groove in the casing cover 14 by a lower oil pipe, a circulating oil loop is formed between the oil reservoir and the oil groove, and waterless dry-running protection is achieved using thermosyphon effect of oil.

Centrifugal pump discharge flange is connected to a check valve 22. When the pump discharges, a gasket 23 in the check valve 22 is upwards horizontally stretched to guarantee that water is freely passing through; when the pump is just started, during evacuation, because of the action of gravity, the gasket 23 is sagged and is attached to the check valve, when the pressure in the pump chamber is gradually reduced, the outside atmospheric pressure acts on the gasket 23 to make the gasket 23 to seal the pump chamber to prevent the outside air from entering.

The drive end of the shaft 2 is connected to an engine, and when the engine is a diesel engine, the shaft 2 will be fitted with a rubber-metal style coupling 3 to connect the diesel engine's flywheel, and when the engine is an electric motor, the shaft will be fitted with a flexible coupling to connect the electric motor's shaft.

As shown in Fig. and FIG. 5, a self-priming rotary sliding vane type of vacuum pump, comprising a rotor and a stator.

For the rotor part: bearings (50) are mounted at both ends of a shaft (44) to support the rotor to rotate, each of the bearings is axially fixed to the shaft (44) by a lock nut (51) and a lock washer (52), radial slots are stretched in the positions of the rotor (47) symmetrical about the center to mount the slide vanes (46), the rotor (47) is tightly fitted on the shaft (44), a hole is drilled in the bottom of the radial slots of the rotor (47) together with the shaft (44) to mount a push lever (45).

For the stator part: a volute (56) is provided with a suction 62 and a discharge 61, a hexagonal socket plug (55) is used to discharge oil of the volute (56), the driving end and non-drive end cover (58) is fitted with the volute (56), is tightened by a bolt (59), and is sealed by an O ring (57), the bearings (50) of the rotor part are mounted in the driving end and non-drive end cover (58) to support the rotor to rotate in the volute; a drive end bearing cover (60) and a non-drive end bearing cover (53) are fixedly mounted on the driving end and non-drive end cover (58) by bolts, and are fitted with the gasket (54) for sealing.

The shaft 44 of the rotary sliding vane type of vacuum pump is driven to rotate by the electromagnetic clutch 27 and the pulley belt assembly 4, the slide vanes 46 are driven to rotate close to the inner surface of the chamber of the volute 56 by the rotor 47, an airtight chamber is formed by two adjacent slide vanes and the inner surface of the chamber of the volute, when the slide vanes 46 rotate from the discharge to the suction: the volume of the airtight chamber is gradually increased and the intensity of pressure is reduced, air is pressed in the airtight chamber when the airtight chamber passes through the suction, the airtight chamber is filled with air and is rotated to the discharge of the pump, the combined total length of the two slide vanes 46 mounted symmetrically about the center and the push lever 45 between the slide vanes is unchanged, the airtight chamber space fitted with the irregular curved surface of the volute is gradually reduced, the intensity of pressure is gradually increased, and air is discharged out of the pump chamber of the vacuum pump when passing through the discharge. This process is repeated so that air at the suction may be quickly moved to the discharge of the volute through the pump chamber and then discharged out of the pump chamber to complete vacuumization.

The vacuum pump 7 is mounted on the frame 9 by the pedestal 8, the shaft 2 in the frame 9 penetrates from the rear side of the frame 9, and the penetrating section of the shaft 2 is connected to the shaft 44 of the vacuum pump 7 by the pulley belt assembly 4 and the electromagnetic clutch 27. The electromagnetic clutch 27 is normally open, when the electromagnetic clutch 27 is turned on and closed, the vacuum pump shaft 44 synchronously rotates with the rotation of the shaft 2 of the centrifugal pump, and when the electromagnetic clutch 27 is turned off and detached, the vacuum pump stops operating. The suction of the vacuum pump 7 is connected to the eccentric reducer 21 by the exhaust pipe assembly 15, and when the electromagnetic valve 28 is turned on and opened, the vacuum pump 7 is interlinked with the pump chamber of the centrifugal pump.

The specific implementation method is as follows: after the self-priming pump is started, the normally closed flow switch 29 connected to the controller is turned on, the electromagnetic clutch 27 is turned on and closed, the vacuum pump 7 starts to operate, the electromagnetic valve 28 is turned on and opened, and the vacuum pump 7 starts to evacuate the air from the suction pipe and the centrifugal pump through the exhaust pipe assembly 15. After several seconds, when water enters into the eccentric reducer 21, the water flow flushes the flow switch 29's contactor, the flow switch 29 is turned off immediately, the electromagnetic valve 28 is immediately turned off and closed, meanwhile, the electromagnetic clutch 27 connected to the flow switch 29 is immediately turned off, the turned-off clutch is detached from the vacuum pump shaft, and the vacuum pump 7 stops operating and turned into a dormant state (so it is called inertia). After the vacuum pump completes evacuation, the self-priming pump starts to work. The electromagnetic valve 28 on the exhaust pipe assembly 15 is turned off and closed, to prevent water from entering the vacuum pump 7 to cause damage and leakage, and prevent the suction of the self-priming pump from leaking air after the vacuum pump 7 stops operating.

Specific Embodiment 2

As shown in FIG. 2, FIG. 3 and FIG. 6, an inertia vacuum assisted self-priming pump, characterized in that the structure of a dry mounted centrifugal pump is identical to that in specific embodiment 1, and modification is mainly made on the vacuum assisted self-priming device.

A float chamber 21 is mounted at the top of a suction pipe 24, a float chamber cover 38 is mounted at the top of the float chamber 21, the float chamber cover 38 is set with a central through hole, a check valve 18 and an exhaust pipe assembly 15 are mounted in the position above the central through hole, and the exhaust pipe assembly 15 is connected to the suction of the vacuum pump 7. A gasket of float valve 36, a float ball 31 and a stop motion mechanism are arranged in the float chamber 21, wherein the gasket of float valve 36 floats along with the float ball 31 and moves upwards and downwards in the float chamber 21, the gasket of float valve 36 is connected to the float ball 31 by the stop motion mechanism, and the gasket of float valve 36 is driven by the float ball 31 to plug the central through hole of the suction cover 38 when floating upwards to close the exhaust pipe assembly.

The stop motion mechanism includes a lever support 42 connected to the bottom of the suction cover 38, a first lever 34 and a second lever 35 located above the first lever 34 are mounted on the lever support 42, one end of the second lever 35 and one end of the first lever 34 are located below a seal seat of float valve 37 in sequence, the lower end of the seal seat of float valve 37 is connected to the end of the second lever 35 extending below the seal seat of float valve 37, the end of the first lever 34 located below the seal seat of float valve 37 is connected to the float ball 31 by a float valve lever 32 and a U clamp 33, and the other ends of the first lever 34 and the second lever 35 are connected by a lever connecting ring 41. A strainer 43 is arranged above the position where the float chamber 21 is connected to the suction pipe 24 in the float chamber 21.

After the self-priming pump is started, the normally closed flow switch 29 connected to the controller is turned on, the electromagnetic clutch 27 is turned on and closed, the vacuum pump 7 starts to evacuate the air from the suction pipe and centrifugal pump through the exhaust pipe assembly 15, when the pump chamber is filled with water, the float ball floats with the water level until the gasket of float valve is closely attached to the seal seat of float valve to close the exhaust pipe, meanwhile, the water flow in the eccentric reducer flushes the flow switch 29's contactor, the flow switch is turned off immediately, the electromagnetic clutch 27 mounted on the pump shaft of the vacuum pump is immediately turned off, the turned-off clutch is detached from the vacuum pump's shaft, the vacuum pump stops operating and turned to a sleep state, and the vacuum pump completes evacuation. The self-priming pump starts to work. The float switch prevents water from entering the vacuum pump 7 to cause damage and leakage. The check valve 18 on the exhaust pipe assembly 15 prevents the suction of the self-priming pump from leaking air after the vacuum pump 7 stops operating. 

1. An inertia vacuum assisted self-priming pump, characterized by comprising a centrifugal pump and a rotary vacuum pump, wherein a pedestal is fixed above a frame of the centrifugal pump, a rotary vacuum pump is mounted above the pedestal and covered by an enclosure; The centrifugal pump consists of an eccentric reducer, a suction cover, a volute, an impeller, a casing cover, a shaft, an adaptor, a frame and a discharge check valve. The suction cover is fitted onto the front end of the volute, the eccentric reducer is mounted in front of the suction cover, a flow switch is installed on the top of the reducer, a check valve is mounted onto the centrifugal pump discharge flange, the casing cover is fitted onto the rear end of the volute, an oil groove circumferentially surrounding the centrifugal pump shaft is arranged outside of the stuffing box of the casing cover, the casing cover backwards connects to the adapter and frame in sequence, a set of bearings are mounted in the frame, the shaft goes through the frame and then extends out at the driving end to connect a coupling which will either couple to an engine or an electric motor; The non-driving end of the shaft goes through the casing cover and then enters into the volute, the impeller is located at the center or a little bit off center of the volute water passage, and mounted on the shaft; The rotary vacuum pump's shaft drive end is connected to the centrifugal pump shaft drive end by a belt, a pulley and an electromagnetic clutch. The electromagnetic clutch will enable the rotary vacuum pump to rotate simultaneously with the centrifugal pump's shaft or unlink to the centrifugal pump's shaft if needed. A built-in oil reservoir is set inside of the vacuum pump's enclosure which is installed on the top of the pedestal to cover the rotary vacuum pump, two hoses were set to connect the oil reservoir and the oil groove; the inner upper part of the oil reservoir is connected with the upper part of the oil groove in the casing cover by an upper oil pipe, the inner lower part of the oil reservoir is connected with the lower part of the oil groove in the casing cover by a lower oil pipe, a circulating oil loop is formed between the oil reservoir and the oil groove to protect the mechanical seal in case of pump runs dry. A temperature meter is mounted outside of the oil reservoir to monitor the oil temperature.
 2. The inertia vacuum assisted self-priming pump according to claim 1, characterized in that the vacuum assisted self-priming control device comprises flow switch, a single or a dual exhaust pipe assembly, an electromagnetic valve, an electromagnetic clutch, a vacuum pump and a controller, wherein the flow switch is normally closed and mounted at the top of the eccentric reducer, the electromagnetic valve is normally closed and mounted on the exhaust pipe assembly, the electromagnetic clutch is normally open and mounted on the shaft of the vacuum pump, the shaft of the vacuum pump is connected to the shaft drive end of the centrifugal pump by a pulley belt assembly and the electromagnetic clutch, the flow switch controls the power for both of the electromagnetic valve and the electromagnetic clutch by monitoring the water flow in the eccentric reducer to achieve automatic start/stop; Both the flow switch and the exhaust pipe assembly including the electromagnetic valve are mounted at the top of the eccentric reducer, and the eccentric reducer is mounted at the front of the suction cover, when the centrifugal pump is turned on, the normally closed flow switch connected to the controller is turned on, the electromagnetic clutch is turned on and closed immediately, the electromagnetic valve is turned on to open model, the vacuum pump starts to work and evacuate the air inside the suction pipe and the centrifugal pump through the exhaust pipe assembly. after several seconds, when water enters into the eccentric reducer, the water flow flushes the flow switch's contactor, the flow switch will be turned off immediately, the electromagnetic valve is immediately turned off to closed model to prevent the liquid from entering into the vacuum pump, meanwhile the electromagnetic clutch is immediately turned off and detaches from the vacuum pump shaft, the vacuum pump finished its priming, centrifugal pump starts to work, and the vacuum pump then switches to a dormant model.
 3. The inertia vacuum assisted self-priming pump according to claim 1, characterized in that the vacuum assisted self-priming control device may also comprise a flow switch, a float chamber assembly, an electromagnetic clutch, a vacuum pump and a controller, wherein the float chamber is located at the top of the eccentric reducer, a suction chamber cover is mounted at the top of the float chamber, a through hole is set in the center of the suction chamber cover, a gasket of float valve, a float ball and a stop motion mechanism are arranged in the float chamber, the stop motion mechanism includes a lever support connected to the bottom of the suction cover, a first lever and a second lever located above the first lever are rotationally mounted on the lever support, one end of the second lever and one end of the first lever are located below the gasket of float valve in sequence, the lower end of the gasket of float valve is connected to the end of the second lever extending below the gasket of float valve, the end of the first lever located below the gasket of float valve is connected to the float ball by a float valve lever and a U clamp, the other ends of the first lever and the second lever are connected by a lever connecting ring, a strainer is arranged above the position where the float chamber is connected with the suction pipe in the float chamber, the flow switch is mounted at the top of the eccentric reducer, the electromagnetic clutch is mounted on the shaft drive end of the vacuum pump, the shaft of the vacuum pump is connected to the shaft of the centrifugal pump by a pulley belt assembly and the electromagnetic clutch, wherein the gasket of float valve floats along with the float ball and vertically moves upwards and downwards in the float chamber to control the opening or closing of the exhaust pipe; when the centrifugal pump is turned on, the normally closed flow switch is turned on, the electromagnetic clutch is turned on and closed immediately, the vacuum pump starts to run and evacuate the air from the centrifugal pump and the suction pipe through the exhaust pipe assembly, the water will come up through the suction pipe and enter into the float chamber and pump volute, the float ball floats along with the water level until the gasket of float valve is closely attached to the seal seat of float valve to close the exhaust pipe to prevent the water from entering into then vacuum pump, meanwhile, the water flow in the eccentric reducer continues flushing the flow switch's contactor, the flow switch is set to be turned off after a few seconds when the water starts to flushes the flow switch's contactor, when the flow switch turned off, the electromagnetic clutch is immediately turned off, the turned-off clutch is detached from the vacuum pump shaft, the vacuum pump stops operating and enters a dormant state, and the vacuum pump completes evacuation.
 4. The inertia vacuum assisted self-priming pump according to claim 1, characterized in that the used vacuum pump is a rotary sliding vane type of vacuum pump, comprising a shaft, a volute, a casing cover, a rotor, a push lever and slide vanes, wherein a shaft of the rotary sliding vane vacuum pump is connected to the shaft of the centrifugal pump by the electromagnetic clutch and the pulley belt assembly and is driven to rotate, the slide vanes are driven to rotate close to the inner surface of the chamber of the volute by the rotor, an airtight chamber is formed by two adjacent slide vanes and the inner surface of the chamber of the volute, when the slide vanes rotate from the discharge to the suction: the volume of the airtight chamber is gradually increased and the intensity of pressure is reduced, air is pressed in the airtight chamber when the airtight chamber passes through the suction, the airtight chamber is filled with air and is rotated to the discharge of the pump, the combined total length of the two slide vanes mounted symmetrically about the center and the push lever between the slide vanes is unchanged, the airtight chamber space fitted with the irregular curved surface of the volute is gradually reduced, the intensity of pressure is gradually increased, and air is discharged out of the pump chamber of the vacuum pump when passing through the discharge; this process is repeated so that air at the suction may be quickly moved to the discharge of the volute through the pump chamber and then discharged out of the pump chamber to complete evacuation.
 5. The inertia vacuum assisted self-priming pump according to claim 1, characterized in that the pump discharge flange is installed a check valve. 